From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87DEEC43334 for ; Thu, 14 Jul 2022 03:29:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232149AbiGND3I (ORCPT ); Wed, 13 Jul 2022 23:29:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229524AbiGND3G (ORCPT ); Wed, 13 Jul 2022 23:29:06 -0400 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72DE4B7D4; Wed, 13 Jul 2022 20:29:04 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045170;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=23;SR=0;TI=SMTPD_---0VJHMqdX_1657769336; Received: from B-X3VXMD6M-2058.local(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0VJHMqdX_1657769336) by smtp.aliyun-inc.com; Thu, 14 Jul 2022 11:28:59 +0800 Reply-To: xhao@linux.alibaba.com Subject: Re: [PATCH v2 0/4] mm: arm64: bring up BATCHED_UNMAP_TLB_FLUSH To: Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, catalin.marinas@arm.com, will@kernel.org, linux-doc@vger.kernel.org Cc: corbet@lwn.net, arnd@arndb.de, linux-kernel@vger.kernel.org, darren@os.amperecomputing.com, yangyicong@hisilicon.com, huzhanyuan@oppo.com, lipeifeng@oppo.com, zhangshiming@oppo.com, guojian@oppo.com, realmz6@gmail.com, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org References: <20220711034615.482895-1-21cnbao@gmail.com> From: Xin Hao Message-ID: <24f5e25b-3946-b92a-975b-c34688005398@linux.alibaba.com> Date: Thu, 14 Jul 2022 11:28:56 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20220711034615.482895-1-21cnbao@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org Hi barry. I do some test on Kunpeng arm64 machine use Unixbench. The test  result as below. One core, we can see the performance improvement above +30%. ./Run -c 1 -i 1 shell1 w/o System Benchmarks Partial Index              BASELINE RESULT INDEX Shell Scripts (1 concurrent)                     42.4 5481.0 1292.7 ======== System Benchmarks Index Score (Partial Only)                         1292.7 w/ System Benchmarks Partial Index              BASELINE RESULT INDEX Shell Scripts (1 concurrent)                     42.4 6974.6 1645.0 ======== System Benchmarks Index Score (Partial Only)                         1645.0 But with whole cores, there have little performance degradation above -5% ./Run -c 96 -i 1 shell1 w/o Shell Scripts (1 concurrent)                  80765.5 lpm   (60.0 s, 1 samples) System Benchmarks Partial Index              BASELINE RESULT INDEX Shell Scripts (1 concurrent)                     42.4 80765.5 19048.5 ======== System Benchmarks Index Score (Partial Only)                        19048.5 w Shell Scripts (1 concurrent)                  76333.6 lpm   (60.0 s, 1 samples) System Benchmarks Partial Index              BASELINE RESULT INDEX Shell Scripts (1 concurrent)                     42.4 76333.6 18003.2 ======== System Benchmarks Index Score (Partial Only)                        18003.2 ---------------------------------------------------------------------------------------------- After discuss with you, and do some changes in the patch. ndex a52381a680db..1ecba81f1277 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -727,7 +727,11 @@ void flush_tlb_batched_pending(struct mm_struct *mm) int flushed = batch >> TLB_FLUSH_BATCH_FLUSHED_SHIFT; if (pending != flushed) { +#ifdef CONFIG_ARCH_HAS_MM_CPUMASK flush_tlb_mm(mm); +#else + dsb(ish); +#endif /* * If the new TLB flushing is pending during flushing, leave * mm->tlb_flush_batched as is, to avoid losing flushing. there have a performance improvement with whole cores, above +30% ./Run -c 96 -i 1 shell1 96 CPUs in system; running 96 parallel copies of tests Shell Scripts (1 concurrent)                 109229.0 lpm   (60.0 s, 1 samples) System Benchmarks Partial Index              BASELINE       RESULT    INDEX Shell Scripts (1 concurrent)                     42.4     109229.0  25761.6                                                                    ======== System Benchmarks Index Score (Partial Only)                        25761.6 Tested-by: Xin Hao Looking forward to your next version patch. On 7/11/22 11:46 AM, Barry Song wrote: > Though ARM64 has the hardware to do tlb shootdown, the hardware > broadcasting is not free. > A simplest micro benchmark shows even on snapdragon 888 with only > 8 cores, the overhead for ptep_clear_flush is huge even for paging > out one page mapped by only one process: > 5.36% a.out [kernel.kallsyms] [k] ptep_clear_flush > > While pages are mapped by multiple processes or HW has more CPUs, > the cost should become even higher due to the bad scalability of > tlb shootdown. > > The same benchmark can result in 16.99% CPU consumption on ARM64 > server with around 100 cores according to Yicong's test on patch > 4/4. > > This patchset leverages the existing BATCHED_UNMAP_TLB_FLUSH by > 1. only send tlbi instructions in the first stage - > arch_tlbbatch_add_mm() > 2. wait for the completion of tlbi by dsb while doing tlbbatch > sync in arch_tlbbatch_flush() > My testing on snapdragon shows the overhead of ptep_clear_flush > is removed by the patchset. The micro benchmark becomes 5% faster > even for one page mapped by single process on snapdragon 888. > > > -v2: > 1. Collected Yicong's test result on kunpeng920 ARM64 server; > 2. Removed the redundant vma parameter in arch_tlbbatch_add_mm() > according to the comments of Peter Zijlstra and Dave Hansen > 3. Added ARCH_HAS_MM_CPUMASK rather than checking if mm_cpumask > is empty according to the comments of Nadav Amit > > Thanks, Yicong, Peter, Dave and Nadav for your testing or reviewing > , and comments. > > -v1: > https://lore.kernel.org/lkml/20220707125242.425242-1-21cnbao@gmail.com/ > > Barry Song (4): > Revert "Documentation/features: mark BATCHED_UNMAP_TLB_FLUSH doesn't > apply to ARM64" > mm: rmap: Allow platforms without mm_cpumask to defer TLB flush > mm: rmap: Extend tlbbatch APIs to fit new platforms > arm64: support batched/deferred tlb shootdown during page reclamation > > Documentation/features/arch-support.txt | 1 - > .../features/vm/TLB/arch-support.txt | 2 +- > arch/arm/Kconfig | 1 + > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/tlbbatch.h | 12 ++++++++++ > arch/arm64/include/asm/tlbflush.h | 23 +++++++++++++++++-- > arch/loongarch/Kconfig | 1 + > arch/mips/Kconfig | 1 + > arch/openrisc/Kconfig | 1 + > arch/powerpc/Kconfig | 1 + > arch/riscv/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/um/Kconfig | 1 + > arch/x86/Kconfig | 1 + > arch/x86/include/asm/tlbflush.h | 3 ++- > mm/Kconfig | 3 +++ > mm/rmap.c | 14 +++++++---- > 17 files changed, 59 insertions(+), 9 deletions(-) > create mode 100644 arch/arm64/include/asm/tlbbatch.h > -- Best Regards! Xin Hao